X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavfilter%2Fscale.c;h=eaee95fac6a9edd6197d1400e9094d76e60befde;hb=704b774ae0290dd8f2f30ba7c6f7427d0c6180c6;hp=50cd442849bfd3a161f638e15b3f45b393b25bfe;hpb=426f5e66a6cb9a453782e9f06c524104c1c3ed02;p=ffmpeg

diff --git a/libavfilter/scale.c b/libavfilter/scale.c
index 50cd442849b..eaee95fac6a 100644
--- a/libavfilter/scale.c
+++ b/libavfilter/scale.c
@@ -60,6 +60,49 @@ enum var_name {
     VARS_NB
 };
 
+/**
+ * This must be kept in sync with var_names so that it is always a
+ * complete list of var_names with the scale2ref specific names
+ * appended. scale2ref values must appear in the order they appear
+ * in the var_name_scale2ref enum but also be below all of the
+ * non-scale2ref specific values.
+ */
+static const char *const var_names_scale2ref[] = {
+    "PI",
+    "PHI",
+    "E",
+    "in_w",   "iw",
+    "in_h",   "ih",
+    "out_w",  "ow",
+    "out_h",  "oh",
+    "a",
+    "sar",
+    "dar",
+    "hsub",
+    "vsub",
+    "ohsub",
+    "ovsub",
+    "main_w",
+    "main_h",
+    "main_a",
+    "main_sar",
+    "main_dar", "mdar",
+    "main_hsub",
+    "main_vsub",
+    NULL
+};
+
+enum var_name_scale2ref {
+    VAR_S2R_MAIN_W,
+    VAR_S2R_MAIN_H,
+    VAR_S2R_MAIN_A,
+    VAR_S2R_MAIN_SAR,
+    VAR_S2R_MAIN_DAR, VAR_S2R_MDAR,
+    VAR_S2R_MAIN_HSUB,
+    VAR_S2R_MAIN_VSUB,
+    VARS_S2R_NB
+};
+
 int ff_scale_eval_dimensions(void *log_ctx,
     const char *w_expr, const char *h_expr,
     AVFilterLink *inlink, AVFilterLink *outlink,
@@ -72,7 +115,16 @@ int ff_scale_eval_dimensions(void *log_ctx,
     int factor_w, factor_h;
     int eval_w, eval_h;
     int ret;
-    double var_values[VARS_NB], res;
+    const char scale2ref = outlink->src->nb_inputs == 2 && outlink->src->inputs[1] == inlink;
+    double var_values[VARS_NB + VARS_S2R_NB], res;
+    const AVPixFmtDescriptor *main_desc;
+    const AVFilterLink *main_link;
+    const char *const *names = scale2ref ? var_names_scale2ref : var_names;
+
+    if (scale2ref) {
+        main_link = outlink->src->inputs[0];
+        main_desc = av_pix_fmt_desc_get(main_link->format);
+    }
 
     var_values[VAR_PI]    = M_PI;
     var_values[VAR_PHI]   = M_PHI;
@@ -90,23 +142,35 @@ int ff_scale_eval_dimensions(void *log_ctx,
     var_values[VAR_OHSUB] = 1 << out_desc->log2_chroma_w;
     var_values[VAR_OVSUB] = 1 << out_desc->log2_chroma_h;
 
+    if (scale2ref) {
+        var_values[VARS_NB + VAR_S2R_MAIN_W] = main_link->w;
+        var_values[VARS_NB + VAR_S2R_MAIN_H] = main_link->h;
+        var_values[VARS_NB + VAR_S2R_MAIN_A] = (double) main_link->w / main_link->h;
+        var_values[VARS_NB + VAR_S2R_MAIN_SAR] = main_link->sample_aspect_ratio.num ?
+            (double) main_link->sample_aspect_ratio.num / main_link->sample_aspect_ratio.den : 1;
+        var_values[VARS_NB + VAR_S2R_MAIN_DAR] = var_values[VARS_NB + VAR_S2R_MDAR] =
+            var_values[VARS_NB + VAR_S2R_MAIN_A] * var_values[VARS_NB + VAR_S2R_MAIN_SAR];
+        var_values[VARS_NB + VAR_S2R_MAIN_HSUB] = 1 << main_desc->log2_chroma_w;
+        var_values[VARS_NB + VAR_S2R_MAIN_VSUB] = 1 << main_desc->log2_chroma_h;
+    }
+
     /* evaluate width and height */
     av_expr_parse_and_eval(&res, (expr = w_expr),
-                           var_names, var_values,
+                           names, var_values,
                            NULL, NULL, NULL, NULL, NULL, 0, log_ctx);
-    eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
+    eval_w = var_values[VAR_OUT_W] = var_values[VAR_OW] = (int) res == 0 ? inlink->w : (int) res;
 
     if ((ret = av_expr_parse_and_eval(&res, (expr = h_expr),
-                                      var_names, var_values,
+                                      names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
         goto fail;
-    eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
+    eval_h = var_values[VAR_OUT_H] = var_values[VAR_OH] = (int) res == 0 ? inlink->h : (int) res;
     /* evaluate again the width, as it may depend on the output height */
     if ((ret = av_expr_parse_and_eval(&res, (expr = w_expr),
-                                      var_names, var_values,
+                                      names, var_values,
                                       NULL, NULL, NULL, NULL, NULL, 0, log_ctx)) < 0)
         goto fail;
-    eval_w = res;
+    eval_w = (int) res == 0 ? inlink->w : (int) res;
 
     w = eval_w;
     h = eval_h;
@@ -122,13 +186,10 @@ int ff_scale_eval_dimensions(void *log_ctx,
         factor_h = -h;
     }
 
-    if (w < 0 && h < 0)
-        eval_w = eval_h = 0;
-
-    if (!(w = eval_w))
+    if (w < 0 && h < 0) {
         w = inlink->w;
-    if (!(h = eval_h))
         h = inlink->h;
+    }
 
     /* Make sure that the result is divisible by the factor we determined
      * earlier. If no factor was set, it is nothing will happen as the default